The ocean and the atmosphere control Earth's climate, and in turn climate and atmospheric changes influence the ocean. We explore the circulation of the ocean and atmosphere, their chemical compositions and their interactions that make up the climate system, including exchanges of heat and carbon. We then investigate how these circulations control marine ecosystems and the biological and chemical cycles of the Earth system. The final part of the course focuses on human impacts, including changes in coastal environments and acidification and warming that result from increased atmospheric carbon dioxide. One weekly precept complements lectures.